The following relates to monitoring arts. It finds particular application in conjunction with monitoring and treating of Obstructive Sleep Disordered Breathing (OSDB). It finds more particular application in monitoring and treating sleep apnea and will be described with a particular reference thereto. However, it is to be appreciated that the following is also applicable to monitoring and treatment of other physiological conditions.
Snoring typically manifests OSDB. OSDB includes upper airway resistance syndrome, non-obstructive and obstructive sleep apneas and nocturnal Cheyne-Stokes breathing. While snoring is characterized by partial occlusion of the upper airway passage during sleep, the sleep apnea and Cheyne-Stokes breathing is normally characterized by intermittently complete occlusions.
Sleep apnea is the most common piece of OSDB and is characterized by the absence of breathing for a certain period of time such as 30 to 45 seconds. Doctors estimate that about 18 million Americans suffer from sleep apnea. One cause for sleep apnea is an obstruction of the airway when the muscles of the tongue or uvula relax. Obesity and an abnormal amount of fat in the throat area are conducive to this condition. Another cause is a temporary cessation of the message from the brain that tells the diaphragm to breathe. In sleep apnea, with each period of breathlessness, which can be as many as twenty in an hour, the carbon dioxide level in the blood rises. There is a corresponding decrease in the blood oxygen levels. This, along with the stress and the struggle to draw breath, puts a strain on the heart. Untreated, sleep apnea can cause high blood pressure and other cardiovascular disease, memory problems, weight gain, impotency, and headaches. If the sleep apnea is diagnosed and treated sooner, such problems might be avoided in some cases, or at least the damage might be reduced.
Polysomnography is a standard diagnostic approach to detect the sleep apnea. It requires the person to stay overnight in the hospital for observation. A polysomnographic procedure involves tethered connections and monitoring of many parameters which makes it intensive, site dependent, and costly. Such approach is not practical for screening a large number of patients and thus the majority of patients suffering from OSDB remain undiagnosed.
One approach to treat sleep apnea is to use a face mask and a small air compressor or fan that forces just enough air through the nasal passages to keep the nasal passages open during the night. But, although such a mask allows a good night's sleep, it causes physical discomfort to the person as well as makes the person prone to nasal congestion and infections.
Another approach is to pace the heart at a faster rate, which stimulates the sleeper's breathing. Unfortunately, this requires an implantable pacemaker type device to the heart.
Another approach is to pace or stimulate the muscles of the tongue or uvula from relaxation thus opening the constricted airway allowing the sleeper to resume breathing. Unfortunately, this approach requires an implantable nerve or muscle stimulator.
Another approach is to surgically remove a portion of the posterior tongue or uvula muscles so that when the muscles relax the airway remains sufficiently open to not totally occlude airflow. Unfortunately, this approach requires a surgical procedure and has not been proven to be a long-term solution.
In yet another approach, the nerves are stimulated by a high voltage shock to the sleeper to condition the sleeper to resume breathing. Such method is painful and might result in a nervous injury.